I posit that the migration, division, and fate of neural stem cells in the adult SVZ is altered following ischemic injury. First I will characterize the normal biology of the adult SVZ, migration patterns, cell fate, and clonality of migrating cells using retroviral marking in vivo. This will be accomplished by two BrdU staining paradigms. One will identify the phenotype and location of S-phase cells at 1, 3, 7, 14 and 28 days by pulsing single BrdU injections at the time point of interest followed by sacrifice two hours later. The second paradigm involves BrdU injections for six consecutive days followed by sacrifice at 7, 14, and 28 days after the initial BrdU injection to determine cell fate and phenotype of dividing cells that accumulate over the course of one week. Unbiased stereology and confocal microscopy will provide data on absolute numbers and locations of each cell. Finally, it has been observed that increasing neuronal number (i.e. transplant) following stroke improves behavioral outcome. This section of the project attempts to determine if amplifying or suppressing stem cell activity and/or neurogenesis in response to injury changes functional outcome. This question will be addressed by influencing stem cell fate through expressing pro-neuronal or pro-glial (i.e., neurogenic) proteins such as noggin or NeuroD1 or bmp4 and jagged-1 respectively. Dr. Tim Schallert has developed sensitive and detailed methods of behavioral assessment focused on limb asymmetry. These methods will be used to assess if enhancing glial or neuronal fate influences behavioral outcome.